1"Bhikkhus, a bhikkhunī endowed with faith, rightly aspiring, should aspire thus: ‘May I become like the bhikkhunīs Khemā and Uppalavaṇṇā!’ This is the standard and criterion for my bhikkhunī disciples, that is, the bhikkhunīs Khemā and Uppalavaṇṇā."[n.320] The two chief bhikkhunī disciples respectively in regard to wisdom and psychic potency. See AN1.236 & AN1.237.

1"Saddhā, bhikkhave, bhikkhunī evaṁ sammā āyācamānā āyāceyya:  ‘tādisī homi yādisī khemā ca bhikkhunī uppalavaṇṇā cā’ti. Esā, bhikkhave, tulā etaṁ pamāṇaṁ mama sāvikānaṁ bhikkhunīnaṁ yadidaṁ khemā ca bhikkhunī uppalavaṇṇā cā"ti.